Having explored a wide range of phenomena in the grammar of the finite verb phrase in Chapters 2 to 8, we will now turn to developments in the field of non-finite verb forms. As in the discussion of the subjunctive, the focus will be on subordinate clauses in complex sentences. A particular problem facing the analysis is the degree of abstractness and generality aimed at in the description. If we decide to focus on a specific non-finite complement structure – such as, say, the to-infinitival clause or the gerund with possessive/genitive modifier – we will find these structures serving a large variety of functions, with most of them not being involved in current diachronic change. If, on the other hand, we decide to focus on more specific constructions – combinations of particular superordinate predicates and particular patterns of complementation (such as, for example, variation between infinitives and gerunds with accustomed to) – we can easily home in on areas of ongoing diachronic change, without, however, being able to correlate individual shifts in usage preferences with general trends in the evolution of the system of English non-finite verbal forms.

To provide a balanced account of developments, the present chapter will draw on both perspectives. Section 9.1 presents the long-term historical background to ongoing changes, pointing out that in the history of English, non-finite subordinate clauses have emerged as strengthened grammatical categories. Section 9.2 follows this up with four detailed case studies.